Development of Pitch Cycle-Based Iterative Learning Contour Control for Thread Milling Operations in CNC Machine Tools

The helical contour motion accuracy of feed drive axes is important for thread milling operations in computer numerical control (CNC) machine tools. However, the dynamics and external disturbances significantly affect results, while perform motions operations. Although existing iterative learning (ILCC) methods can improve accuracy, problems data recording processing on memory usage computational burden systems, wasted materials, increased costs manufacturing still limit practical applications ILCC. Therefore, considering similar during pitch cycle a path, this study developed cycle-based (PCB-ILCC) method to address system caused by use For PCB-ILCC, adopted error vector estimation referring interpolated positions path simplify complexity designed ILCC using easily implement structure. Thus, permanent magnet synchronous motor (PMSM) driving utilizing robust mitigate axes. Thread experiments performed five-axis CNC machining center demonstrated feasibility PCB-ILCC validated that it achieve an 80% reduction rate comparison with proportional–proportional–integral control, which extensively used commercialized PMSM drivers controllers.